This core will be co-directed by Drs. Dawna Armstrong and Jeffrey Noebels. It has developed from an original Neurocytology Image Analysis Core, directed by Dr. J. Noebels which operated during the initial years of the Mental Retardation Research Center. That core served to provide digital imaging capabilities for brain neurochemistry and for molecular genetic data analysis. With the increasing use of various tissues (muscle, brain, conjuctiva and nerve) in the study of mental retardation, neuropathology facilities, directed by Dr. Armstrong, were added to the core. The demand for neuropathologic studies on both human and animal tissues has increased significantly over the past two years and has required the expansion of the Neuropathology Laboratory. In recent years the availability of various animal models for mental retardation and epilepsy has required the addition of electroencephalography (EEG). The core utilization has been extensive and has been expanded to include, in Dr. Noebels laboratory, EEG monitoring of mutant animals, and in Dr. Armstrong's laboratory, morphology of animal models for diseases associated with mental retardation. The core functions as two separate laboratories, Neuropathology directed by Dr. Armstrong and EEG, directed by Dr. Noebels. Since much of the research in the past few years has centered on lesions affecting the developing nervous system, the neuropathology facility is now designated as Developmental Neuropathology.